Pernicious anemia affects around 1 in 680 people in the United States. Pernicious anemia is a blood disorder and an autoimmune disorder caused by the body’s inability to properly absorb vitamin b12, leading to a loss of red blood cells and low platelet count, which can cause a variety of symptoms and can even lead to different types of anemia. Although not a life threatening disease, if left untreated, permanent nerve and brain damage can occur. Once diagnosed, pernicious anemia is easy to treat with B12 injections or supplements.
Unlike the more commonly known sickle cell anemia, the shape of the red blood cells is not altered; instead the production of red blood cells is reduced. Every day the body is exposed to a number of toxins, called antigens. These antigens are foreign substances that enter the body, such as chemicals, bacteria, viruses, or pollen. The body produces antibodies to destroy the harmful antigens. In some people, the body does not distinguish between healthy and unhealthy substances and will produce antibodies against normal body tissue and cells; this is called an autoimmune disorder. In pernicious anemia, the body produces antibodies to destroy the intrinsic factor or the cells that produce the intrinsic factor. The intrinsic factor is a protein that is produced by parietal cells, or stomach cells, which also create HCl, or stomach acid. Intrinsic factor binds to vitamin b12 and helps it dissociate so that it can be absorbed into the blood stream. Without it, b12 cannot be absorbed in the stomach, leading to an array of medical complications.
Vitamin b12 is an important for cell metabolism, DNA formation, and energy production. It also plays an important role in the formation of red blood cells, hence the development of anemia. Red blood cells bind to oxygen and distribute it to the body’s tissues through the circulatory system. A lack of blood cells means that tissues will not receive the oxygen they need to be healthy and survive. Along with the development of anemia, b12 deficiency can lead to fatigue, depression, and memory loss.
Symptoms of pernicious anemia or b12 deficiency are most commonly fatigue and weakness, abnormally rapid heartbeat, shortness of breath, numbness or tingling in the hands and feet, and chest pains. Symptoms are usually mild and not life threatening. Because they are so mild pernicious anemia can sometimes go undiagnosed. Different types of anemia can result from pernicious anemia, such as megaloblastic anemia. In most cases pernicious anemia does not develop until after the age of 30 and is most common after the age of 60. In rare cases babies can be born with the inability to produce the intrinsic factor but it usually takes decades to fully develop which is why it’s seen later on in life rather than at an early age. Over time if left untreated permanent nerve and brain damage can occur.
Several tests can be done to see if a person has pernicious anemia including a shilling test, which measures b12 deficiency, a b12 level test, a complete red blood count test, and a bone marrow examination. The most efficient way to test for pernicious anemia is the Intrinsic Factor Antibody Test, which detects the presence of antibodies that destroy the intrinsic factor. Pernicious anemia can be a genetic disorder, so some people have a predisposition for the disease. It is impossible to prevent because the reason why the body starts producing antibodies against the intrinsic factor is unknown. Although it cannot be prevented it is easily treated with either a monthly b12 injection or a daily high dose b12 supplement.